Session Title: Quick Fire Free Paper Session
Session Date/Time: Saturday 17/02/2018 | 11:45-13:00
Paper Time: 12:30
Venue: Ballroom II & III.
First Author: : L.Frizziero ITALY
Co Author(s): : R. Parrozzani D. Londei G. Miglionico S. Trainiti E. Pilotto E. Midena
To propose a clinical grading of peripapillary vascular changes in radiation optic neuropathy (RON) using optical coherence tomography angiography (OCT-A).
This was an institutional, observational, cross-sectional study, with prospective enrolment. Patients were recruited from those referred to the ocular oncology centre of the University of Padova, and the G.B. Bietti Foundation between November 2016 and April 2017.
Thirty-four patients treated by Iodine-125 brachytherapy because of a posterior uveal melanoma and affected by RON were consecutively included. The radial peripapillary capillary plexus (RPCP) and the entire peripapillary capillary bed (EPCB) were analysed using OCT-A (Nidek RS-3000, Nidek, Gamagori, Japan). Quantitative perfusion analysis (vessel area density, vessel length fraction and vessel density index) of the OCT-A slabs was performed using ImageJ software (National Institutes of Health, Bethesda, MD). Qualitative analysis (Grade 0: absence of vessels abnormalities; Grade 1: loss of the radial pattern of the peripapillary vasculature in absence of vessels dropout; Grade 2: presence of peripapillary dropout in less than 180°; Grade 3: presence of RPCP dropout in more than 180°; Grade 4: presence of a complete RPCP dropout or extensive peripapillary changes that make OCT-A unreadable) was also performed by two masked graders.
The mean time between Iodine-125 brachytherapy and RON diagnosis was 3.9 years (SD: 2.73 years). Mean BCVA of treated eyes was 74.5 ETDRS score (SD, 6.9 years) at time of brachytherapy and 51.7 ETDRS score (SD, 8.4) at patient inclusion. RPCP and EPCB quantitative perfusion parameters were significantly reduced in eyes affected by RON (p<0.001 and p<0.01, respectively). RPCP-based clinical grading of RON correlated with the quantitative RPCP perfusion analysis (p=0.0001) and ETDRS visual acuity score (p=0.001). EPCB-based clinical grading of RON also correlated with the quantitative EPCB perfusion analysis and ETDRS visual acuity score (p=0.02 and p=0.01, respectively). RPCP-based clinical grading of RON reached the highest inter-grader agreement (0.96 vs 0.86).
The use of OCT-A allows to clinically detect RPCP and EPCB peripapillary vascular changes secondary to RON. Compared to the EPCB-based clinical grading, the RPCP-based clinical grading reached a superior inter-grader agreement. The proposed RPCP-based clinical classification of RON is supported by the quantitative perfusion analysis obtained by specific images elaboration techniques, and correlates with ETDRS visual acuity score.